Plant this...Not that - Norway maple

Dense fall foliage and dominance of the canopy, mid-story, and understory by Norway maple (Acer platanoides). (Image: Art Gover)

Norway Maple

Acer platanoides

Not That!

Information by Art Gover

Alternative

Consider Native Maples, like the Red, Sugar, or Silver.

Abstract

Do not plant Norway maple, and if you have it, replacing it would be a good yard project. It produces dense shade, is adapted to a wide range of soil types, and is available in many cultivars such as the red-leafed “Crimson King”. However, it is a poor host for insects and reduces forest diversity in natural settings.

Foliage and seed of Norway maple. (Image: Leslie J. Mehrfhoff, UConn, Bugwood.org)

Description

Norway maple (Acer platanoides) is a tree species native to Europe, introduced into American horticulture in the late 1700s by John Bartram. It has a rounded form and grows up to 60+ feet tall. Its leaves display the familiar maple form, with 5 to 7 lobes (Figure 1). It is distinguishable from the similar but native sugar maple (Acer saccharum) by its blunt, green terminal buds and the milky sap that oozes from the leaf petiole when plucked from the stem. Norway maple holds its leaves later in the season than native maples and displays fairly uniform yellow fall color. Like native maples, the bark is smooth and gray when young but gets dark with tight fissures as it matures.

Natural History

Norway maple's native range is Scandinavia south to Turkiye, and Spain east to Afghanistan. It has spread into western Asia and has been introduced to the British Isles and North America (Kew Gardens, Plants of the World Online). It produces abundant seed, in the familiar winged samara (“helicopter”) that flutters away from the parent. Norway maple seed germinates readily in the shade, and over time forests become less diverse as young Norway maples are best-suited to tolerate the heavy shade of mature plants. This dense shade reduces the diversity of woody seedlings as well as the herbaceous plants on the forest floor.

Norway maple can be distinguished from the similar sugar maple (Acer saccharum) by the visible milky sap exuded from leaf stems (Image: Leslie J. Mehrfhoff, UConn, Bugwood.org).

Why You Should Not Plant This

In addition to reducing the diversity of understory plants, Norway maple is poor habitat for the bugs that feed songbirds and great habitat for ticks. Few insects, particularly lepidoptera (moths, butterflies) use Norway maple as a host plant. It occupies space in your landscape but does not benefit desired wildlife.

Defenders of Norway maple cite the reduced viability and abundance of seed from cultivars. This does render the landscape plant less prolific, but as soon as the cultivar is cross-pollinated by a “wild type” Norway maple, the offspring revert to wild, highly fertile form and begin spreading. Planting reduced-fertility cultivars delays the spread into the adjacent landscape but does not prevent it. It also still does not create habitat for insects.

Do not plant Norway maple, and if you have it consider replacing it with native trees. If you value the shade, plant the replacement trees close to the maple, and as they mature, you can remove the Norway maple when they are big enough to provide useful shade. It’s the Long Game, but the ecosystem that is your yard will benefit.